You're presuming that it was AI which killed the kid, rather than some kind of emotional or social condition.
It's so easy to call for a ban on a thing that you see as bad when it's an emotional subject, and particularly when there are, say, incentivized evangelists who constantly reinforce the idea to attack the symptom when you can't get at the disease itself.
Which can work in some cases. There aren't a lot of effective medications for a lot of mental illnesses, and investments in research of ones which will work better is a huge expense with disincentives for success. If you "cure" or provide a drug with a higher duration of efficacy for cheaper with fewer side effects, what do you get? Well, you spent hundreds of millions figuring out how to sell 1 pill instead of 10.
The same disincentives exist for the idea of forcing doctors to insist on therapy as a treatment. If it works longer term by addressing roots of issue (if), the doc isn't getting a recurring patient every month to sign off on prescriptions, and the drug company's not getting that prescription.
Changing health and social systems isn't going to get a politician much credit. The effects of improvement are hard to quantify. The choices are HARD, and it takes years to see whether the change was good or bad.
So there's resistance to changing health and social systems.
It's a lot easier to DEMAND our politicians do something, anything, even if it's clearly a bad idea. We want to know they're at least trying.
Something violent happens, blame video games because they show violent things. It's easy and simple. Very catchy to the common man. An easy way to virtue signal that you want something done without having to actually dive in and understand all of the factors around why that bad thing just happened. You can put your energy into something simple and then go about your day.
Then you don't have to consider the impacts of rising wealth inequality, lack of social programs to detect and intervene, the quality and capacity of schools to foster healthy social environments for children, the availability and access to mental health resources, availability and access to automatic rifles, or hell, even the way your own kid has learned to treat other children and which part of your parenting processes contribute to that.
It's sooo much easier to pick a thing and cry "Boycott that! Legislate that!" instead.
And now we, collectively as a society, are doing the same with AI. And special interest groups are fanning the flames, to build moats around profit centers.